[mythtv-users] Jerky Playback on only one channel - OTA HD CBS

[Calvin Harrigan]

    I've been pouring over the archives looking for someone who has had 
a similar problem.  I've been using mythtv for a little while, about 5 
years 7 months 14 days 22 hrs 9 mins according to mythweb.  I upgraded 
to HD early last year (2007) with the purchase of a HDHR.  Everything 
worked great.  I am able to record HD/SD, play them back fine, no 
worries.  In extreme cases  I have recorded two HD streams, one sd, and 
played back another HD simultaneously without fault..  This fall season, 
I started to record two shows on CBS, a channel that I don't recall ever 
recording from.  The Ghost Whisperer and The Mentalist.  The shows 
record fine, but during playback the video jerks something fierce.  
It'll play fine for a few seconds then slow down/ pause, then pick back 
up, it does this through the entire show.  I thought maybe it was CPU, 
but the CPU is almost idling, it doesn't get about 30% total.  I thought 
it might be something with the deinterlacer, so I checked the detected 
interlace setting, sometimes it showed up as progressive, other times 
interlaced.  I know it's supposed to be progressive (1080i), so I force 
it to interlaced when it detects progressive, but that doesn't fix the 
problem.  I'm looking for any ideas, things to try to fix the only 
problem I have with mythtv.

The computer specs are:

AMD Athlon 64 X2 3800+
2 Gigs DDR2 800 MHz
400 gig Seagate - system/non-recorded video/pictures/music/etc
750 gig Seagate - recordings
1 PVR - 250
1 HDHR
On board video nvidia 6150 on an Asus M2NPV-VM
On Board Audio and NIC.
Running Gentoo - Linux mythtv 2.6.24-Gentoo-r8 #6 SMP
Kernel - 2.6.24
Nvidia Driver - 173.14.09
Xorg - 7.2
xorg server - 1.3.0.0-r6
Mythtv - 0.21_p18314